Early repolarization pattern on ECG recorded before the acute coronary event does not predict ventricular fibrillation during ST-elevation myocardial infarction

Background: Generally considered benign, electrocardiographic (ECG) early repolarization (ER) pattern was claimed to be an indicator of increased susceptibility to ventricular arrhythmias during acute ischemia. Objective: The purpose of this study was to assess in a nonselected population whether ER pattern documented before ST-elevation myocardial infarction (STEMI) is associated with risk of hemodynamically unstable ventricular tachycardia (VT) or ventricular fibrillation (VF) during acute STEMI. Methods: For STEMI patients admitted for primary percutaneous coronary intervention from 2007–2010, the latest ECGs recorded before STEMI were exported in digital format. After excluding ECGs with paced rhythm and QRS duration ≥120 ms, the remaining ECGs were processed using the Glasgow algorithm allowing automatic ER detection. The association between ER pattern and VT/VF during the first 48 hours of STEMI was tested using logistic regression. Results: ECGs recorded before STEMI were available for 1584 patients. Of these patients, 124 did not meet inclusion criteria, leaving 1460 patients available for analysis (age 68 ± 12 years; 67% male). ER pattern was present in 272 patients (18.6%; ER+ group). ER+ and ER– groups did not differ with regard to clinical characteristics. VT/VF during the first 48 hours of STEMI occurred in 19 ER+ (7.0%) and 105 ER– patients (8.8%; P =.398). ER was not associated with any VT/VF (odds ratio [OR] 0.78; 95% confidence interval [CI] 0.47–1.29; P =.324); VT/VF before reperfusion (OR 0.48; 95% CI 0.23–1.001; P =.051); or reperfusion-related VT/VF (OR 1.28; 95% CI 0.55–3.01; P =.569). Conclusion: In a nonselected population of STEMI patients, the ER pattern on ECG recorded before the acute coronary event was not associated with VT/VF during the first 48 hours of STEMI.